Just one day after finishing his sentence for acts he was convicted of more than three decades ago, Rivera returned to the neighborhood Thursday for a celebration, which started outside La Casita de Don Pedro, 2625 W. Division St.

A group, led by a float adorned with a smaller version of Humboldt Park's iconic steel Puerto Rican flags, then marched down Division Street before landing at Mozart Street to unveil a street sign named in honor of Rivera.

Local politicians and supporters Ald. Roberto Maldonado (26th), Ald. Carlos Ramirez-Rosa (35th), Ald. Joe Moreno (1st) and U.S. Rep Luis Gutierrez (D-Ill.), as well as community leaders such as Billy Ocasio from the National Puerto Rican Museum of Art, all came out to celebrate.

During his remarks, Maldonado, a longtime friend of Rivera, called the event a "special homecoming." He said Rivera's "political beliefs have inspired us all."

The Humboldt Park alderman introduced Rivera, who received mostly a warm welcome from more than a hundred supporters chanting, "Oscar's free," and waving Puerto Rican flags.

Speaking to the crowd, Rivera said he loves the Humboldt Park community, which is where he spent many years as a community organizer.

"For the future of Puerto Rico, I believe in the youth ... to transcend anything," Rivera said.

At one point during the ceremony, a fight broke out between a few of Rivera's supporters and Mark Heller, a longtime resident of Logan Square, who was holding a sign that read, "Terrorist OLR." Heller's sign was ripped in half. Nearby police officers broke up the fight.

Mark Heller, who doesn't think Rivera should be honored, claims he was assaulted in the crowd.

Heller said he doesn't support the honorary street sign because Rivera advocated for a "socialist, independent, Marxist state by any means necessary, including terrorist bombings, maiming and killing innocent civilian victims for [his] cause."

A couple more fights broke out both during and after the ceremony between another man and Rivera supporters. There were no arrests reported.

In 1981, Rivera, now 74, was convicted of federal charges, including seditious conspiracy to overthrow the U.S. government, when he was a member of Fuerzas Armadas de Liberación Nacional. The group, known as FALN, claimed responsibility for many bombings in major U.S. cities between 1974 and 1983. He was sentenced to 55 years in prison.

Rivera was one of 64 people who was granted a shortened sentence or, in some cases, a pardon by President Barack Obama right before Obama left office.

Rivera was born in Puerto Rico but moved to Humboldt Park, one of the city's largest Puerto Rican enclaves, as a teenager. He went on to become an activist in the community before going off to fight in Vietnam.

His brother, Jose Lopez, has become one of Humboldt Park's most prominent figures as one of the founders of the Puerto Rican Cultural Center and a fixture in local politics.

Rivera's supporters waiting for him to arrive.

For years, many Humboldt Park residents have been calling for Rivera to be freed, painting murals around the neighborhood and marching in his honor at neighborhood-wide events.

Rivera is seen as either a political hero or a criminal.

His supporters say his prosecution and conviction was politically motivated. He has said FALN was "adhering to international law that says that colonialism is a crime against humanity and that colonial people have a right to achieve self-determination by any means, including force.”

Others had warned against a pardon, saying Rivera didn't deserve one. He became a fugitive in 1976 when investigators reportedly discovered what they called a "bomb factory" in his Chicago apartment.

The parade down Division Street.

Joseph Connor, the son of a FALN bombing victim, has called the street sign a "disgrace."

"It is sinister. It’s a direct insult to my father’s life," Connor told the Sun-Times. "The commutation was politically driven. But to honor in the second-largest city in the United States the leader of the terrorist group that murdered my father? It is so over the top, shameful and disgusting and vile, reprehensible.”